Apparatus and method for transmitting 10 Gigabit Ethernet LAN signals over a transport system

ABSTRACT

A computer system and method for transmitting 10 Gigabit Ethernet (10GE) LAN signals over transport systems. Standard 10GE LAN signals are generated in any client IEEE 802.3 10GE LAN compliant interface. A transceiver receives the client 10GE LAN signal in the LAN format. The client 10GE LAN signals are not converted to a SONET transmission format at any time before reaching the transceiver. The transceiver then converts the client 10GE LAN signal to an internal electrical 10GE LAN signal before re-clocking the internal electrical LAN signal. The re-clocked internal electrical 10GE LAN signal is then re-modulated into a second 10GE LAN signal. The second 10GE LAN signal is then transmitted to a transport system.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 10/357,606, entitled “Apparatus and Method for Transmitting 10Gigabit Ethernet LAN Signals over a Transport System,” filed Feb. 4,2003, which claims priority to Provisional Application Ser. No.60/370,826, entitled “Apparatus and Method for Transmitting 10 GigabitEthernet LAN Signals Over a Long Haul DWDM System”, by Jeffrey Lloyd Coxand Samir Satish Seth, filed Apr. 8, 2002.

FIELD OF THE INVENTION

This invention relates to a computer system for transmitting a 10Gigabit Ethernet local area network (LAN) signal over a transport systemwithout encapsulating the 10GE LAN signal into a Synchronous OpticalNetwork (SONET) frame.

BACKGROUND OF THE INVENTION

Data networks that cover large geographical distances have historicallybeen fundamentally different from those that cover short distances. Thisfact primarily was derived from the different evolutionary paths thatwere followed by the Enterprise networks (ones that reside inside of abusiness, home, educational institution, or government agency) and theCarrier networks (ones that are provided by a common carrier). Over thepast few decades the Enterprise networks and Carrier networks mostlyevolved independently, each addressing a different problem and eachfollowing a different set of standards. The Enterprise networks mostlyevolved to support data from computing environments via LANinfrastructures and data protocols. After decades of competition betweendifferent LAN standards and networking protocols during the 1980s and1990s, the LANs are now predominantly built on Ethernet and InternetProtocol (IP) technologies. Ethernet is defined by the Institute forElectrical and Electronics Engineers (IEEE) and specifically is definedby the IEEE 802.3 standard. The Internet Engineering Task Force (IETF)defines IP.

The Carrier networks mostly evolved to support voice services from homeand business customers via various circuit-switched Time DomainMultiplexing (TDM) technologies. The Carrier networks are nowpredominantly comprised of various TDM technologies built on theSynchronous Optical Network (SONET) standard or its European counterpartSynchronous Digital Hierarchy (SDH). The American National StandardInstitute (ANSI) defines SONET and the International TelecommunicationsUnion (ITU) defines the SDH standard.

Historically, the Ethernet LAN technologies provided very cost-effectivehigh-speed “local” connections among computers, but sacrificed theability to span distances longer than approximately 10 km. TypicalEthernet LANs spanned relatively small areas like a building or acampus. Such a transport system may be called an inter-office transportsystem. More recently, Ethernet has been used directly over opticalfiber in Metropolitan Area Networks (MANs) to deliver Ethernet servicesnatively to areas on the order of 100 km in diameter. The method on howto utilize Ethernet natively on optical fiber for distances shorter thanapproximately 100 km is specified by the IEEE 802.3 standard.

As the need arose for the Enterprise LAN networks to interconnect theirgeographically separate facilities, the only available services at theEnterprise's disposal were from the public Carriers' networks. However,the asynchronous, connectionless, packet-oriented nature of the LANtechnology was mostly incompatible with the synchronous,connection-based, bit-oriented nature of the Carriers' TDM facilities.To join the two technological worlds together, various data technologieswere invented. In the realm where speeds are comparable to that of LANs(i.e. 10 Megabits/second or greater) Asynchronous Transfer Mode (ATM),Frame Relay (FR), and Packet over SONET (POS) became the most populardata technologies that Carriers utilized. ATM, FR, and POS are generallyconsidered Wide Area Networking (WAN) technologies and are built on topof the SONET-based TDM infrastructure currently deployed by thecarriers. In general, ATM, FR, and POS sacrificed the simplicity,efficiency, and cost-effectiveness of LAN technologies in order to becompatible with the existing carrier TDM infrastructure, which wasprimarily designed for voice traffic. At the time ATM, FR, and POS werebeing developed in the late 1980s, it made sense to make thesesacrifices because the volume of data traffic over the TDMinfrastructure was insignificant when compared to the volume of voicetraffic. However, since the later part of the 1990's, data traffic hasgrown exponentially so that now it comprises the majority of the trafficon the Carrier's TDM infrastructure.

Since Carriers adopted ATM, FR, and POS as the WAN technologies,Enterprise networks were forced to utilize these inefficient andexpensive technologies to interconnect their LANs between their variouslocations. Typically the interconnections were accomplished via routerswith ATM, FR, and POS interfaces and ATM switches, see FIG. 1. Theintroductions of these WAN technologies to the Enterprise's LANinfrastructures lead to significant new technological learning curvesand significant capital and operational expenses. Many Enterprisescreated entirely separate departments to deal with the Carriers andtheir WAN technologies.

As the Ethernet LAN technologies evolved, data rates grew from 10Mbits/sec to 100 Mbits/sec, 1 Gbit/sec, and now 10 Gbit/sec Ethernet(10GE). Each successive generation of Ethernet remained compatible withthe previous, thus allowing for interoperability as the network grew.Enterprises quickly adopted each new generation of Ethernet technologyto support the exploding traffic volumes on their LANs. With theintroduction of 10GE standard, Enterprise networks will once again scaleto the next level. The high throughput rate of 10GE makes the technologyextremely attractive for use on corporate backbone networks. Because theoriginal packet format and minimum/maximum packet size were retainedbetween the various versions of Ethernet, all forms of Ethernetinteroperate seamlessly. Consequently it is possible, for example, tocollect traffic from one hundred 100 Base-T Ethernets, each running atfull speed, and pass this traffic along a single 10GE network.

However, the Carrier WAN technologies have lagged behind the LANEthernet implementations in terms of capacity, price/performance, andease of use. Enterprises have voiced their desire to implement Ethernetconnections across WANs as a mechanism to supplant the traditional WANtechnologies (ATM, FR, and POS) offered by Carriers. There are severalpotential mechanisms available to transport the various Ethernettechnologies across WAN infrastructures. In general, these mechanismscan be broken into two categories: encapsulation and native. In the caseof encapsulation, an Ethernet frame is removed from its native mediaformat and encapsulated inside of the payload area of another protocol.There are numerous examples of the encapsulation approach including:Ethernet over FR, Ethernet over POS, Ethernet over SONET (x86, 10GE WAN,and others), and Ethernet over ATM (LANE). All of these encapsulationtechniques were invented in order to allow Ethernet to be run overexisting Carrier WAN technologies that, in turn, were transported on topof traditional Carrier TDM technologies, thus creating additionalunnecessary layers of cost and complexity. The native Ethernet formatsare defined by the IEEE 802.3 committee standards for each of theEthernet variations. The physical layer (PHY) of the IEEE Ethernetstandards defines how Ethernet is transmitted over a given media. Foreach of the Ethernet speeds (10 Mb, 100 Mb, 1 Gb, and 10 Gb) the IEEEdefines at least one native PHY format that transports Ethernet directlyon optical fiber facilities and at least one PHY format that transportsEthernet directly on copper facilities (coax or twisted pair media). Inaddition to various copper-based PHYs, each of the Ethernet speedssupport multiple PHYs for optical fiber in order to support differentreaches, different price points, and different optical fiber types.However, the IEEE-defined PHYs do not support:

-   -   1. Reaches beyond about 100 km    -   2. Optical media other than optical fiber    -   3. Media other than optical fiber or copper    -   4. Multiplexing multiple Ethernet signals over a given optical        media.

The 100 km limit on optical fiber is the approximate point at which anoptical signal will degrade beyond the point of recovery without someform of signal regeneration. The IEEE 802.3 committee's charter ended atthis point as they saw that distances beyond 100 km were in the realm ofWAN technologies and they were a committee chartered to focus on LANissues.

When developing the 10GE standard, the IEEE 802.3ae committee developedtwo different 10GE frame formats. These frame formats are generallyknown as the “LAN” standard and the “WAN” standard, though these aresomewhat misnamed terms. The 10GE “LAN” standard utilizes a native frameformat identical to all previous IEEE 802.3 Ethernet standards. But, inorder to allow compatibility with the existing SONET framing structureand data rate, the IEEE 802.3ae committee defined the 10GE “WAN”standard. The IEEE 802.3ae WAN standard encapsulates native Ethernetframes inside of an OC-192 SONET Payload Envelope (SPE) and adjusts theclock rate of the 10GE signal such that it is compatible with that ofOC-192. Both the 10GE WAN and 10GE LAN standards support the same set ofoptical fiber PHYs and thus both have the same distance limitations on asingle span of optical fiber without resorting to additional equipment.The “LAN” and “WAN” designations simply refer to their differences inframing format and data rates.

To transport native Ethernet signals further than the nominal 100 kmlimit on optical fiber, and/or to support multiple optical Ethernetsignals natively on a given optical fiber, other technologies must beintroduced to multiplex, amplify, and condition the optical signal. Thetechnologies that allow optical signals to cost-effectively travelbeyond 100 km and/or be multiplexed on optical fiber are well known andhave been applied to the SONET industry for well over a decade. Thesetechnologies include: optical amplification (via Erbium Doped FiberAmplifiers (EDFA) or Raman amplifiers), dispersion compensation, opticalmultiplexing via Coarse Wave Division Multiplexing (CWDM, less than 17channels) or Dense Wave Division Multiplexing (DWDM, greater than orequal to 17 channels), gain equalization, Forward Error Correction(FEC), and various modulation techniques. Combined, these technologiesare generally referred to as Metro (less than 100 km in length), LongHaul (LH, between 100 and 1000 km), and Ultra Long Haul (ULH, greaterthan 1000 km) transport systems. Recent ULH systems allow more than 100ten-gigabit signals to be transmitted 1000's of kilometers over anoptical fiber without the need to be converted to an electronic signal.

Transport systems are that class of systems that allow a signal (orsignals) to be transmitted and received via a media while includingfunctionality beyond that of the original signal. An optical transportsystem may include optical fiber or free space optics. A fiber transportsystem can include fiber optics, copper wire, or any thread likesubstance, such as carbon fiber, capably of carrying a signal. Transportsystems include support for functionality such as (but not limited to):

-   -   1. Media: optical fiber, Free Space Optics (FSO), Radio        Frequency (RF), and electrical-based solutions (twisted copper        pairs, coaxial cable)    -   2. Topological organizations: linear, rings, stars, and meshes    -   3. Switching capabilities: protection, restoration, and        cross-connections    -   4. Multiplexing capabilities: single channel, CWDM, and DWDM    -   5. Directional capabilities: unidirectional or bi-directional    -   6. Distance capabilities: Metro, LH, ULH, submarine, and        satellite systems    -   7. Transport system network elements: Optical Add/Drop        Multiplexers (OADM), Optical Wavelength Cross-connects (OXC),        and Regenerators (Regen)    -   8. Management and Control systems: signaling protocols,        performance monitoring, and configuration and control interfaces

These functionalities may be used independently or in variouscombinations to create a wide variety of transport systemimplementations to solve specific transport system problems.

In the prior art, to adapt a standard IEEE 802.3 10GE client signal to aformat that is suitable for a specific transport system, a device calleda transceiver is employed. A transceiver converts the 10GE signal from aclient system (the tributary signal) to a signal that is defined by theparticular transport system (the line signal). Prior art transceiverssuch as those offered by Nortel, Lucent, Hitachi and others areavailable to convert 850, 1310 and 1550 nm optical tributary signalscompatible with the 10GE WAN standard to the signals suitable for theirrespective Metro/LH/ULH systems. However, a need exists in the industryfor a transceiver that is capable of receiving tributary signals of the10GE LAN standard. In other words, a need exists for a high-speedtransport system that is compatible with the 10GE LAN standard and doesnot require conversion to the IEEE 10GE WAN standard, or any otherSONET-based standard, for use in creating networks.

Prior art systems suffer from the ability of using the 10GE LAN standardfor a high-speed transport system. For example, United States Patent No.2001/0014104, to Bottorff, et al., entitled “10 Gigabit EthernetMappings For A Common Lan/Wan Pmd Interface With A Simple UniversalPhysical Medium Dependent Interface”, discloses an Ethernet mapping thatenables high speed Ethernet data streams having a data rate of 10 Gb/sto be transported across a synchronous packet switched network having astandard SONET OC-192 line rate. The Bottorff invention, as with many ofthe other prior art inventions, requires conversion to a SONET-basedstandard.

U.S. Pat. No. 6,075,634 to Casper, et al., entitled “Gigabit Data RateExtended Range Fiber Optic Communication System And TransponderTherefor”, discloses a method and system for a fiber optic digitalcommunication system and associated transponder architecture. The systeminterfaces Gigabit Ethernet digital data over an extended range fiberoptic link, using digital data signal regeneration and optical signalprocessing components that pre- and post-compensate for distortion andtiming jitter. Casper does not disclose a transceiver that is capable ofreceiving tributary signals of the 10GE LAN standard.

U.S. Pat. No. 6,288,813 to Kirkpatrick, et al., entitled “Apparatus AndMethod For Effecting Data Transfer Between Data Systems”, discloses areceiver that converts an optical signal to digital data signals. Thedigital data signals are then converted to balanced bipolar signals andare then outputted onto buses for input into data systems. Kirkpatrickdoes not disclose an architecture for transporting 10GE LAN signals.

SUMMARY OF THE INVENTION

The present invention is an improvement over the prior art because theinvention provides a system and method for transmitting IEEE 10GE LANsignals over transport systems through a novel transceiver. Standard10GE LAN tributary signals are generated by any IEEE 802.3 10GE LANcompliant client device or system. The transceiver receives thetributary 10GE LAN signal in its native format. The transceiver thenconverts the 10GE LAN signal to an internal electrical 10GE LAN signaland utilizes this signal to drive a second transport system signal (theline-side or line signal). The line-side 10GE LAN signal is thentransmitted through the remainder of the transport system as a standard10GE LAN signal with or without FEC.

The invention further provides for performance monitoring (PM) of thereceived tributary and line-side optical signals, termination of thetributary and line signals (both transmit and receive), conversion ofthe tributary and line signals to and from internal electrical signals,electrically multiplexing and de-multiplexing signals, adding andremoving FEC, clock and data recovery (CDR) of received signals, and inthe case of optical line-side signals, control of laser wavelengthlocking and modulation of line optics.

An exemplary use of the invention consists of the interconnection of two10GE LAN client systems such as that known in the art. One example wouldbe the Cisco Catalyst 6500 Ethernet switch with a 10GE LAN interface(the client interface). The Catalyst 10GE LAN interface is connected toan embodiment of the invention comprising of a 10GE LAN transceiver,which is in turn connected to a transport system. The transport systemcarries the 10GE LAN signal to the other end of the transport systemwhere a second 10GE LAN transceiver coverts the signal to a secondclient signal that is attached to a second Catalyst 10GE LAN interface.Within each transceiver, the 10GE client signal is converted to and froman internal electrical signal via the PMD. The internal 10GE signal isperformance monitored by a 10GE LAN Media Access Control (MAC) circuit.The internal 10GE signal is connected through a bus to and from aForward Error Correction (FEC) circuit and subsequently to an electricalmultiplexer (MUX) and from an electrical de-multiplexer (DMUX) where CDRis performed. The data from the electrical MUX is then communicated to aline optics module (LOM) in the transmitting direction of the line-side.The transmitting direction of the LOM consists of one or more drivers(electrical amplifiers) that modulate (either directly or via anexternal modulator) a laser contained in the LOM. The resultingmodulated laser light is then placed onto the transport system. Thereceiving direction of the LOM consists of a detector and an electricalamplifier to boost the detected signal in the case where the detector'sown electrical signal is insufficient to drive the remaining circuitry.Data from the electrical detector is then communicated to DMUX where CDRis performed and the signal is subsequently passed to the FEC circuit.The PMD, 10GE MAC, FEC circuit, MUX, DMUX, and LOM are all controlledfrom a central micro controller through a control bus.

All of the above advantages make a high-speed transport system that iscompatible with the 10GE LAN standard and does not require conversion tothe IEEE 10GE WAN standard, or any other SONET-based standard, for usein creating networks. This results in an increase of capacity, a betterprice/performance ratio, and a system that is easier to use and operate.

DETAILED DESCRIPTION OF THE DRAWINGS

A better understanding of the invention can be obtained from thefollowing detailed description of one exemplary embodiment as consideredin conjunction with the following drawings in which:

FIG. 1 a is a block diagram depicting a transport system connectingmultiple LANs according to the prior art POS approach;

FIG. 1 b is a block diagram depicting a transport system connectingmultiple LANs according to the ATM approach;

FIG. 2 a is a block diagram depicting a transport system connectingmultiple LANs according to the present invention in a layer 3 routerapproach;

FIG. 2 b is a block diagram depicting a transport system connectingmultiple LANs according to the present invention in a layer 2 switchapproach;

FIG. 3 is a block diagram of the 10GE LAN transceiver according to thepresent invention;

FIG. 4 is a block diagram depicting a LOM according to the presentinvention;

FIG. 5 is a block diagram depicting two variations of transport systemsserially connected to one another according to the present invention;and

FIG. 6 is a block diagram depicting a 10GE LAN regenerator according tothe present invention.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS

In the descriptions that follow, like parts are marked throughout thespecification and drawings with the same numerals, respectively. Thedrawing figures are not necessarily drawn to scale and certain figuresmay be shown in exaggerated or generalized form in the interest ofclarity and conciseness. Reference of an A-Z signal or direction meansfrom the left side of the drawing to the right side of the drawing whileZ-A means from the right side to the left side. The A-Z or Z-Adesignation is used for illustrative purposes only.

FIG. 1 illustrates the block diagram of a transport systeminterconnecting multiple LANs according to the prior art. FIG. 1illustrates two different typical prior art approaches: The POS approach(FIG. 1 a) and the ATM approach (FIG. 1 b). In both approaches, thetransport system 100 is connected at both ends by OC192 SONETtransceivers 110 a, 110 b, 110 y and 110 z.

For the POS approach in FIG. 1 a, Ethernet-based secondary systems 101a-f are connected to Ethernet switches 104 a and 104 b via Ethernetsignals 121. Ethernet signals 121 may be 10 Mb, 100 Mb, or 1 Gb and arebased on the IEEE 802.3 standard, herein incorporated by reference.Switches 104 a and 104 b are connected to router 106 a via 10GE LANsignals 122. Router 106 a is connected to transceiver 110 a via OC192SONET POS signal 120 a. Transceiver 110 a is connected to transportsystem 100. Transport system 100 is connected to transceiver 100 y.Transceiver 100 y is connected to router 106 z via POS signal 120 b.Router 106 z is connected to switches 104 y and 104 z via 10GE LANsignals 122. Switches 104 y and 104 z are connected to Ethernet-basedsecondary systems 102 a-f via Ethernet signals 121.

The communications to and from secondary systems 101 a-f throughswitches 104 a and 104 b and to router 106 a occurs via Ethernetpackets. To communicate over transport system 100, router 106 a convertsthe standard Ethernet LAN packets existing on 10GE LAN signals 122 toPOS signal 120 a. The POS signal 120 a frame format differs in form fromthe standard 10GE LAN signal 122 frame format and conversion is requiredfrom one to the other. Routers 106 a and 106 z communicate over POSsignal 120 a and 120 b in a point-to-point fashion utilizing the POSprotocol. The transceivers 110 a and 110 y at either end of thetransport system 100 do not participate at the POS protocol level withthe routers 106 a and 106 z and therefore the routers 106 a and 106 zappear to each other as if they are directly connected.

For the ATM approach in FIG. 1 b, Ethernet-based secondary systems 103a-1 are connected to switches 104 c-f via Ethernet signals 121. Switches104 c-f are connected to routers 106 b-e via 10GE LAN signals 122.Routers 106 b-e are connected to ATM Switches 118 a and 118 b via OC48ATM signals 124. ATM Switches 118 a and 118 b are connected to SONETAdd/Drop Multiplexers (ADM) 112 a and 112 b via ATM signals 124. SONETADMs 112 a and 112 b are connected to a SONET Broadband Cross-connect(BXC) 113 a via an OC192 SONET ring 126 a. BXC 113 a is connected totransceiver 110 b via an OC192 SONET TDM signal 123 a. Transceiver 110 bis connected to transport system 100. Transport system is connected totransceiver 110 z. Transceiver 110 z is connected to BXC 113 z via TDMsignal 123 b. BXC 113 z is connected to SONET ADMs 112 y and 112 z viaSONET ring 126 b. SONET ADMs 112 y and 112 z are connected to ATMSwitches 118 y and 118 z by ATM signals 124. ATM switches 118 y and 118z are connected to routers 106 v-y via ATM signals 124. Routers 106 v-yare connected to switches 104 u-x via 10GE LAN signals 122. Switches 104u-x are connected to Ethernet-based secondary systems 104 a-1 viaEthernet signals 121.

The communications to and from the secondary systems 103 a-1, Ethernetswitches 104 c-f, and routers 106 b-e occurs via Ethernet packets. Tocommunicate over transport system 100, routers 106 b-e convert standardEthernet LAN packets existing on 10GE LAN signals 122 to ATM signal 124.The ATM signal 124 frame format 124 differs in form from the standard10GE LAN signal 122 frame format and conversion is required from one tothe other. The standard ATM signal 124 is switched via the ATM switches118 a and 118 b and transported into ATM signal 124 time-slots on theSONET ring 126 a by the ADMs 112 a and 112 b. The ATM signal 124 timeslots on the SONET ring 126 a are removed by the BXC 113 a and arecross-connected onto ATM signal 124 time-slots on TDM signal 123 a. TDMsignal 123 a is then placed onto transport system 100 by transceiver 110b.

Routers 106 b-e and routers 106 v-y can communicate with each other viastandard ATM virtual circuits (VCs) that flow through the ATM switches118 a-b and 118 y-z and are transported over the ADMs 112 a-b and 112y-z, SONET ring 126 a, BXC 113 a and 113 z, and transceivers 110 b and110 z. The transceivers 110 b and 110 z, ADMs 112 a-b and 112 y-z, SONETrings 126 a and 126 b, BXC 113 a and 113 z, and TDM signal 123 a and 123b do not participate at the ATM protocol level with the ATM switches 118a, 118 b, 118 y and 118 z, and therefore the ATM switches 118 a, 118 b,118 y and 118 z appear to each other as if they are directly connected.Additionally, the ATM switches 118 a, 118 b, 118 y and 188 z do notparticipate in the routing protocols run on the routers 106 b-e and 106v-y and thus the routers 106 b-e and 106 v-y also appear as if they aredirectly connected to each other.

FIG. 2 is a block diagram depicting a transport system interconnectingmultiple LANs in accordance with the present invention. FIG. 2illustrates two different approaches that could be utilized. FIG. 2 arepresents the layer 3 Router approach. FIG. 2 b represents the Layer 2Switch approach. In both approaches, the transport system 100 isconnected to Ethernet networks by 10GE LAN transceivers 200 a-b and 200y-z.

For the Layer 3 Router approach in FIG. 2 a, secondary Ethernet systems101 a-f, as shown in the prior art system of FIG. 1 a., are connected toswitches 104 a and 104 b via Ethernet signals 121. Switches 104 a and104 b are connected to router 106 a via 10GE LAN signals 122. Router 106a is connected to 10GE LAN transceiver 200 a via 10GE LAN signal 122 a.10GE LAN transceiver 200 a is connected to transport system 100.Transport system 100 is connected to 10GE LAN transceiver 200 y. 10GELAN transceiver 200 y is connected to router 106 z via 10GE LAN signal122 y. Router 106 z is connected to switches 104 y and 104 z via 10GELAN signals 122. Switches 104 y and 104 z are connected to secondarysystems 102 a-f via Ethernet signals 121.

The standard 10GE LAN signal 122 a is transmitted from the router 106 athrough the 10GE LAN transceiver 200 a continuing through the transportsystem 100 through the 10GE LAN transceiver 200 y and to the router 106z without conversion at the frame level, thus creating an end-to-endEthernet infrastructure. Routers 106 a and 106 z are capable ofsupporting 10GE LAN signals 122 a and 122 y and such an interface iswell known in the art and will not be further described here. The 10GELAN signals 122 pass from the router 106 z to switches 104 y and 104 z.The 10GE Ethernet LAN frame as defined in the IEEE 802.3 specificationis not altered in transit through the transceiver or transport system.

For the Layer 2 Switch approach in FIG. 2 b, secondary ethernet systems103 a-1 are connected to switches 104 c-f via Ethernet signals 121.Switches 104 c-f are connected to the Layer 2 Ethernet switch 117 a via10GE LAN signals 122. Layer 2 Ethernet switch 117 a is connected to 10GELAN transceiver 200 b via 10GE LAN signal 122 b. 10GE LAN transceiver200 b is connected to transport system 100. Transport system 100 isconnected to 10GE LAN transceiver 200 z. 10GE LAN transceiver 200 z isconnected to the Layer 2 Ethernet switch 117 z via 10GE LAN signal 122z. Layer 2 Ethernet switch 117 z is connected to switches 104 u-x via10GE LAN signals 122. Ethernet switches 104 u-x are connected tosecondary systems 104 a-1 via Ethernet signals 121. The standard 10GELAN signal 122 b is transmitted from the Layer 2 Ethernet switch 117 athrough the 10GE LAN transceiver 200 b, through the transport system 100through the 10GE LAN transceiver 200 z and to the Layer 2 Ethernetswitch 117 z without conversion at the frame level.

According to the present invention, the standard 10GE LAN signal 122 a,122 b, 122 y, and 122 z are not converted to a standard SONET signal 120prior to reception by transceivers 200 a, 200 b, 200 y, and 200 z. Forexample, the standard 10GE LAN signal 122 b is transmitted directly fromthe Layer 2 Ethernet switch 117 a through the 10GE LAN transceiver 200 bwithout conversion to the standard ATM signals 124, standard SONET ring126 a or SONET TDM signal 123 a as was required in the prior art systemof FIG. 1 b. 10GE LAN transceivers 200 a, 200 b, 200 y, and 200 z ofFIG. 2 receive a standard 10GE LAN signal 122 a, 122 b, 122 y, and 122z, not a SONET POS signal 120 a or a SONET TDM signal 123 a. Becauseconversions from the 10GE LAN signals to standard ATM signals andstandard SONET ring and TDM signal are not required, ATM switches 118,SONET ADMs 112, and SONET BXCs 113 required by the prior art are notrequired in a network incorporating the present invention.

FIG. 3 is a block diagram of 10GE LAN transceiver 200. 10GE LANtransceiver 200 includes a physical medium device (PMD) 301 able toreceive a 10GE LAN signal 122 a and transmit a 10GE LAN signal 122 b.The specifications for various PMDs for the 10GE LAN standard aredefined in the IEEE 802.3 specification and are well known in the art.Laser temperature, laser current (optical PMDs) and “loss of signal”information is transmitted to micro-controller 350 from PMD 301 throughcontrol line 351 to monitor the performance of PMD 301. Also, themicro-controller 350 is able to control the PMD 301 through control line351.

Upon receiving a 10GE LAN signal 122 a, PMD 301 converts the standard10GE LAN signal 122 a into a standard electrical 10GE LAN signal 308.The electrical 10GE LAN signal 308 from PMD 301 is transmitted to anelectrical de-multiplexer (De-Mux) chip 304. Standard electrical 10GELAN signal 308 is transmitted by the PMD 301 at the same serial datarate 10.3125 Gb/sec as the standard 10GE LAN signal 122 a and is definedby IEEE 802.3 standard. De-Mux 304 recovers clock and data informationand divides the serial standard electrical 10GE LAN signal 308 into anintermediate 16-channel wide 10GE LAN signal 326 transmitted in parallelformat to the 10GE LAN media access controller (MAC) chip 312. Statusinformation such as bit error rate (BER) and chip identification aretransmitted to micro-controller 350 from De-Mux 304 via line 352 asrequired to maintain optimal system performance. PMD 301 is alsoconnected to an electrical multiplexer (Mux) 302 through serial standard10GE LAN electrical signal 306. Mux 302 combines an intermediate16-channel wide 10GE LAN signal 324 transmitted from the MAC 312 into a10GE LAN serial signal at 10.3125 Gb/sec that is transmitted to PMD 301through line 306. Mux 302 communicates with micro-controller 350 throughline 353, transmitting status information and chip identification codes.

Transponder modules 310 that combine PMD 301, Mux 302 and De-Mux 304 arecommercially available and typically identified as 10 G Multi-SourceAgreement (MSA) Transponder modules (300-pin or 200-pin), XenPak, Xpak,or XFP Transponder modules. Variations of the transponder modules 310commercially exist to support a variety of media, optical fiber types,wavelengths, and reaches according to the IEEE 802.3 specification. Anexample MSA module 310 includes the Network Elements MiniPHY-300 thatcan be used to convert a 1310 nm optical signal to an electrical signaland convert an electrical signal to a 1310 nm optical signal. Inaddition, a wide variety of other commercially available transpondermodules can also be implemented to accomplish this task. In thepreferred embodiment, transponder module 310 may be changed before orduring operation to accommodate various 10GE LAN client applications.

MAC 312 provides for a standard IEEE 802.3 10GE LAN MAC implementationas specified by the IEEE 802.3 standard. MAC 312 is used as aperformance-monitoring device for the intermediate 10GE LAN signals 326and 328. The MAC 312 monitors the packet data, idle, preamble and theremaining sections of the standard 10GE LAN signals as defined by theIEEE 802.3 standard. MAC 312 also identifies the total number of packetspresent, the total number of bytes present, performs cyclic redundancychecks (CRC) to detect errors in each packet, and performs numerousother packet monitoring functions as defined by the IEEE 802.3 standard.MAC 312 then communicates this performance monitoring information tomicro-controller 350 via line 354. The micro-controller 350 also usesline 354 to instruct MAC 312 to be configured in such a way that theintermediatel OGE LAN signals 326 and 328 pass through MAC 312unmodified while the performance monitoring information is extracted.Further, micro-controller 350 is able to receive copies of 10GE LANframes from MAC 312 via line 354.

Micro-controller 350 utilizes the performance monitoring information toreport how the 10GE LAN signal is performing. In one embodiment,micro-controller 350 polls line 354 extracting the number of packeterrors. If certain thresholds are crossed, then an error is reported tothe management system indicating a problem exists. If the errors reach acritical level, then micro-controller 350 can shut down the 10GE LANsignals 122 to prevent promulgation of errors.

The MAC 312 transmits the standard electric intermediate 10GE LAN signal330 to the Forward Error Correction (FEC) device 314. FEC 314 is adevice known in the art and performs the function of adding or deletingredundant information to the input bit pattern to allow it to be encodedand decoded to successfully eliminate errors resulting from transmissionover the transport system 100. The FEC is not required for thefunctionality of the invention but is incorporated in the preferredembodiment for optimal performance. FEC 314 is in communication with Mux318 via signal 334. As the signal is passed from MAC 312 through FEC 314to Mux 318, FEC 314 adds extra data to the bit pattern contained in 10GELAN signal 330 to allow for the recovery of potentially damaged bits in10GE LAN signal 330 after 10GE LAN signal 330 has been transmitted overtransport system 100. FEC 314 divides 10GE LAN signal 330 intopredetermined sizes or frames and adds redundant information to theframes before transmission to Mux 318 via 10GE LAN signal 334.

In the reverse direction, FEC 314 receives FEC-wrapped frames over 10GELAN signal 332 from De-Mux 316 and utilizes the redundant FECinformation to correct data errors up to the FEC algorithm's limit. Ifthe errors exceed the algorithm's limit, FEC 314 notes that the frame'serrors were unrecoverable and reports the unrecoverable frame error tomicro-controller 350 through line 355. If the FEC frame's errors arewithin the FEC algorithm's limit, FEC 314 corrects the frame, extractsthe original 10GE LAN signal and transmits the corrected signal to MAC312 via intermediate 10GE LAN signal 328 for further processing.

Mux 318 combines the parallel signals of the 10GE LAN signal 334 into aserial clock signal 339 and a phase shifted serial data signal 338. Mux318 communicates statistics and chip identification codes tomicro-controller 350 through line 357. The serial clock signal 339 andserial data signal 338 are then transmitted to line optics module (LOM)400.

LOM 400 converts the serial data signal 338 and the serial clock signal339 into optical signal 342. Optical signal 342 has a specificwavelength suitable for transmission over the transport system 100. LOM400 reports measurements on laser drive current, laser bias voltage, andother parameters to micro-controller 350 through line 358.

The above describes an A-Z signal, for a Z-A signal LOM 400 receivesincoming optical signal 340 from the transport system 100. LOM 400converts optical signal 340 into a serial FEC-wrapped 10GE LANelectrical signal 336. The FEC-wrapped 10GE LAN electrical signal 336 isthen transmitted to De-Mux 316. De-Mux 316 recovers clock and datainformation from 10GE LAN electrical signal 336 and divides the serialstandard electrical 10GE LAN signal 336 into an intermediate 16-channelwide 10GE LAN signal 332 transmitted in parallel format to FEC 314.De-Mux 316 communicates with micro-controller 350 through line 356 onthe presence or absence of a usable signal and the BER of the 10GE LANelectrical signal 336.

FEC 314 performs error correction as is described above and transfersthe intermediate 10GE LAN signal 328 to MAC 312. MAC 312 monitors theperformance of the intermediate 10GE LAN signal 328 as previouslydescribed and transparently passes the intermediate 10GE LAN signal 328via signal 324 to Mux 302. Mux 302 recombines signal 324 into a serialstandard 10GE LAN electrical signal 306 that is then transmitted to thePMD 301. PMD 301 converts the standard electrical 10GE LAN signal 306 toa standard 10GE LAN signal 122 b as defined in the IEEE 802.3 standard,and sends standard 10GE LAN signal to router 106 a or switch 117 adepending on the architecture of the system.

FIG. 4 is a block diagram of LOM 400 according to the present invention.In LOM 400, in the direction of a Z-A, an optical FEC-wrapped 10GE LANsignal 340 that has been transmitted over a transport system 100 isreceived by photo detector 414. Photo detector 414 converts the opticalFEC-wrapped 10GE LAN signal 340 to an electrical voltage signal 412.Voltage signal 412, in the range of 50 milli-volts, is then transmittedto amplifier 410 where the voltage of the signal is increased to a rangeof 500 milli-volts. Some models of photo detectors supply adequatevoltage on signal 412 so the amplifier 410 may not be required. Afterthe voltage in signal 412 has been increased by amplifier 410, 10GE LANelectrical signal 336 is sent from the LOM 400 to the De-Mux 316 (asshown in FIG. 3).

In the LOM 400, in the direction of A-Z, serial clock signal 339 fromMux 318 is sent to a modulator driver 434. Serial clock signal 339 maybe on the order of 500 milli-volts. Also, serial data signal 338 fromMux 318 is sent to a second modulator driver 438. Serial data signal 338may also be on the order of 500 milli-volts.

A continuous-wave laser 420 is provided to generate laser optical signal422 with an optical power on the order of 20 milli-watts. Laser 420 islocked to a specific frequency and temperature to produce a specificwavelength on laser optical signal 422. According to the presentinvention, a wavelength of 1520 to 1620 nanometers is desired with anaccuracy of 0.01 nanometers. However, a wide variety of wavelengths andspectral widths can be implemented without detracting from the spirit ofthe invention. The laser optical signal 422 is sent to modulator 424.

In addition to receiving the laser optical signal 422, modulator 424also receives a clock driver signal 432 from modulator driver 434. Clockdriver signal 432 may be on the order of 12-volts. The modulator 424modulates the laser optical signal 422 in accordance with the clockdriver signal 432. The clock-modulated optical signal 426 is thentransmitted to a second modulator 428. In addition to theclock-modulated optical signal 426, second modulator 428 also receives aphase-shifted data input signal 436 from second modulator driver 438.Phase-shifted data input signal 436 may be on the order of 8-volts.Second modulator 428 modulates the clock-modulated optical signal 426 asecond time in accordance with phase-shifted data input signal 436. Thedouble-modulated optical signal 342 is then transmitted from the LOM 400to transport system 100. While FIG. 4 shows the laser is externallymodulated, the laser may also be internally modulated.

FIGS. 5 a and b are block diagrams depicting the use of the invention intwo architectural approaches to extend the reach of a transport system100. Other architectural approaches can be utilized without detractingfrom the spirit of the invention.

In serial transport system architecture 600, shown in FIG. 5 a, separate10GE LAN transport systems 601, 602, and 699 are each equipped with oneor more 10GE LAN transceivers 200 a, 200 b, 200 y and 200 z. Thetransceivers 200 a, 200 b, 200 y and 200 z are operationally connectedto a combination of transport systems 100 a-z and regenerators 500 a and500 b in an alternating arrangement. The ellipsis in the drawingindicates that there could be any number of reiterations of thearchitecture between 602 and 699. The overall system reach of the 10GELAN signals is extended by serially connected adjacent 10GE LANtransceivers (200 a/200 y and 200 b/200 z) to form a continuous signalpath for one or more 10GE LAN signals. By orientating transceivers 200a, 200 b, 200 y and 200 z in such a manner, they act as repeaters.

In the A-Z direction, 10GE LAN signal 122 a is received by transceiver200 a, transmitted over transport system 100 a, and received bytransceiver 200 y. Transceiver 200 y then sends 10GE LAN signal 122 to asecond transceiver 200 a to be transmitted over second transport system100 b. By transceiver 200 y sending 10GE LAN signal 122 to transceiver200 a to be transmitted over a transport system the overall system reachof the 10GE LAN signals is extended. The process of serially connectingadjacent 10GE LAN transceivers continues until the desired distance isreached. Any number of transport systems 100 can be seriallyinterconnected with pairs of 10GE LAN transceivers 200. Just astransceivers 200 a and 200 y can be serially connected to regenerators500 a in the A-Z direction, transceivers 200 b and 200 z can be seriallyconnected to regenerators 500 b in the Z-A direction as is shown in FIG.5.

FIG. 6 is a block diagram of the 10GE LAN regenerator 500. 10GE LANregenerator 500 is a specialized version of a 10GE LAN transceiver 200that lacks the external client 10GE LAN signals 122 a and 122 b. Thepurpose of the 10GE LAN regenerator 500 is to recover signal 504 from atransport system 100 a and process the signal in such a way that signal542 is suitable for retransmission on the next iteration of a transportsystem 100 b (see FIG. 5 b). Going the opposite direction, 10GE LANregenerator 500 could recover signal 540 from a transport system 100 band process the signal in such a way that signal 502 is suitable forretransmission on the next iteration of a transport system 100 a. In thepreferred embodiment, 10GE LAN regenerator 500 includes LOM 400 a thatreceives transport system optical signal 504. LOM 400 a reportsmeasurements on laser drive current, laser bias voltage, and otherparameters to micro-controller 350 through line 551. LOM 400 a convertstransport system optical signal 504 into serial electrical 10GE LANsignal 508 and sends serial electrical 10GE LAN signal 508 to De-Mux512.

De-Mux 512 recovers clock and data information and divides the serialelectrical 10GE LAN signal 508 into an intermediate 16-channel wide 10GELAN signal 526. Status information such as bit error rate (BER) and chipidentification are transmitted to micro-controller 350 from De-Mux 512via line 552 as required to maintain optimal system performance. De-Mux516 performs a similar function on a Z-A signal as De-Mux 512. De-Mux516 recovers clock and data information and divides the serialelectrical 10GE LAN signal 536 into an intermediate 16-channel wide 10GELAN signal 532. De-Mux 516 is in communication with micro-controller 350via line 556 and communicates the same type of status information asDe-Mux 512.

In the A-Z direction, intermediate 10GE LAN signal 526 is communicatedfrom De-Mux 512 to FEC 514 where the FEC algorithms recover any datathat has been corrupted by the transport system 100 a. If the dataerrors exceed the algorithm's limit, FEC 514 notes that the frame's datawas unrecoverable and reports the unrecoverable frame error tomicro-controller 350 through line 554. FEC 514 transfers the correctedsignal 530 to a second FEC 515 where a new set of FEC data is calculatedand added to the signal to create a second data signal 534 thatincorporates the FEC data. In the Z-A direction, intermediate 10GE LANsignal 532 is communicated from De-Mux 516 to FEC 515 where the FECalgorithms recover any data that has been corrupted by the transportsystem 100 a. FEC 515 is in communication with micro-controller 350through line 555 and uses line 555 to report any unrecoverable frameerrors to a signal in the Z-A direction. FEC 515 transfers the correctedsignal 528 to FEC 514 where a new set of FEC data is calculated andadded to the signal to create a second data signal 524 that incorporatesthe FEC data.

In the A-Z direction, data signal 534 is sent to Mux 518 and convertedinto serial data signal 538 and serial clock signal 539. Mux 518communicates statistics and chip identification codes tomicro-controller 350 through line 557. Mux 510 performs a similarfunction on a Z-A signal as Mux 518. Data signal 524 is sent to Mux 510and converted into serial data signal 506 and serial clock signal 507.Mux 510 is in communication with micro-controller 350 via line 553 andcommunicates the same type of status information as Mux 518.

In the A-Z direction, data signal 538 and clock signal 539 arecommunicated to LOM 400 b from Mux 518. LOM 400 b reports measurementson laser drive current, laser bias voltage, and other parameters tomicro-controller 350 through line 558. LOM 400 b converts data signal538 and clock signal 539 into transport system optical signal 542 fortransport over transport system 100 b. In the Z-A direction, data signal506 and clock signal 507 are communicated to LOM 400 a from Mux 510. LOM400 a reports measurements on laser drive current, laser bias voltage,and other parameters to micro-controller 350 through line 551. LOM 400 aconverts data signal 506 and clock signal 507 into transport systemoptical signal 502 for transport over transport system 100 a.

Returning to FIG. 5 b, in serial transport system architecture 700,separate 10GE LAN transport systems 701, 702, 703, and 799 are eachequipped with a 10GE LAN regenerator 500. The ellipsis in the drawingindicates that there could be any number of reiterations of thearchitecture between 703 and 799. In architecture 700, in the A-Zdirection, 10GE LAN signal 122 a is received by transceiver 200 a.Transceiver 200 a transmits the signal over transport system 100 a to10GE LAN regenerator 500 a. 10GE LAN regenerator 500 a and b may beconnected together in series with the transport system 100 b in order toform a continues signal path for one or more of the 10GE LAN signals.The overall system reach of the system is extended through multipleserially connected 10GE LAN regenerators 500 a and b. After the desireddistance is crossed, transceiver 200 y receives the signal fromtransport system 100 and pass 10GE LAN signal 122 y to switch 117 z asdescribed earlier. Any number of transport systems 100 can be seriallyinterconnected with pairs of regenerators 500 a and b. Just as 10GE LANregenerators 500 a and b can be serially connected in the A-Z direction,10GE LAN regenerators 500 a and b can be serially connected in the Z-Adirection as is shown in FIG. 5 b.

The foregoing disclosure and description of the invention areillustrative and explanatory thereof of various changes to the size,shape, materials, components and order may be made without departingfrom the spirit of the invention.

1. A computer system for transmitting 10GE LAN signals over a network,the system comprising: a transponder for communicating a 10GE LANsignal; a multiplexer/de-multiplexer coupled to the transponder; and aline optics module coupled to the multiplexer/de-multiplexer.
 2. Thecomputer system of claim 1 further comprising a micro controller coupledto the transponder, the multiplexer/demultiplexer and the line opticsmodule, wherein the micro controller controls and obtainsperformance-monitoring data from the 10GE LAN signal.
 3. The computersystem of claim 1, wherein the 10GE LAN signal is transmitted at astandard LAN transmission rate.
 4. The computer system of claim 1wherein the 10GE LAN is transmitted with the addition of forward errorcorrection data.
 5. The computer system of claim 1 further comprising amedia access controller operationally connected to the 10GE LAN signal.6. The computer system of claim 1 further comprising a forward errorcorrecting device operationally connected to themultiplexer/de-multiplexer.
 7. The computer system of claim 1 whereinthe line optics module further comprises an optical to electricalconversion means for converting the 10GE LAN signal to an opticalsignal.
 8. The computer system of claim 1 wherein the line optics modulefurther comprises an amplifier to amplify the 10GE LAN signal.
 9. Thecomputer system of claim 1 wherein the line optics module furthercomprises a laser for transmitting the 10GE LAN signal.
 10. The computersystem of claim 9 wherein the laser is internally modulated.
 11. Thecomputer system of claim 9 wherein the laser is externally modulated.12. An architecture for transporting 10GE LAN signals comprising: afirst 10GE LAN transceiver; a first transport system in communicationwith the first 10GE LAN transceiver; and a second 10GE LAN transceiverin communication with the first transport system.
 13. The architectureof claim 12 further comprising the first transceiver being connected toa first router and the second transceiver being connected to a secondrouter.
 14. The architecture of claim 12 further comprising the firsttransceiver being connected to a first switch and the second transceiverbeing connected to a second switch.
 15. The architecture of claim 12wherein the first transport system is unidirectional.
 16. Thearchitecture of claim 12 wherein the first transport system isbi-directional.
 17. The architecture of claim 12 wherein a plurality oftransport systems is serially interconnected with pairs of 10GE LANtransceivers.
 18. The architecture of claim 12 further comprising thefirst and second transceiver operationally connected to a combination oftransport systems and transceivers in an alternating arrangement.